Rework kvm_cpuid() to query entry->function when adjusting the output
values so that the original function (in the aptly named "function") is
preserved for tracing. This fixes a bug where trace_kvm_cpuid() will
trace the max function for a range instead of the requested function if
the requested function is out-of-range and an entry for the max function
exists.
Fixes: 43561123ab37 ("kvm: x86: Improve emulation of CPUID leaves 0BH and 1FH")
Reported-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
Cc: Jim Mattson <jmattson@xxxxxxxxxx>
Cc: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
---
arch/x86/kvm/cpuid.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index b1c469446b07..6be012937eba 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -997,12 +997,12 @@ static bool cpuid_function_in_range(struct kvm_vcpu *vcpu, u32 function)
return max && function <= max->eax;
}
+/* Returns true if the requested leaf/function exists in guest CPUID. */
bool kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx,
u32 *ecx, u32 *edx, bool check_limit)
{
- u32 function = *eax, index = *ecx;
+ const u32 function = *eax, index = *ecx;
struct kvm_cpuid_entry2 *entry;
- struct kvm_cpuid_entry2 *max;
bool found;
entry = kvm_find_cpuid_entry(vcpu, function, index);
@@ -1015,18 +1015,17 @@ bool kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx,
*/
if (!entry && check_limit && !guest_cpuid_is_amd(vcpu) &&
!cpuid_function_in_range(vcpu, function)) {
- max = kvm_find_cpuid_entry(vcpu, 0, 0);
- if (max) {
- function = max->eax;
- entry = kvm_find_cpuid_entry(vcpu, function, index);
- }
+ entry = kvm_find_cpuid_entry(vcpu, 0, 0);
+ if (entry)
+ entry = kvm_find_cpuid_entry(vcpu, entry->eax, index);
}
if (entry) {
*eax = entry->eax;
*ebx = entry->ebx;
*ecx = entry->ecx;
*edx = entry->edx;
- if (function == 7 && index == 0) {
+
+ if (entry->function == 7 && index == 0) {
u64 data;
if (!__kvm_get_msr(vcpu, MSR_IA32_TSX_CTRL, &data, true) &&
(data & TSX_CTRL_CPUID_CLEAR))
--
2.24.1
